Welding rod



Patented Apr. 10, 1934 UNITED STATES 1,954,394 'WELDING ROD Louis A.Meisse, Mansfield, Ohio, assignor to The Ohio Brass Company, Mansfield,Ohio, a corporation of New Jersey No Drawing. Application April 21,1982, Serial No. 606,762

8 Claims.

My invention relates to metallic rods for arc welding in which the rodbecomes the electrode for depositing welding metal upon the article tobe welded.

Among the objects of my invention are the following:

To produce a coated rod for depositing substantially pure copper uponthe article to be welded and which will be dense and homogenous.

To produce a coating for such rod.

A coated rod in which the coating will have a reaction upon the rodunder operation to neutralize the oxidizing effect of the air, thecoating to contain a slag-forming material which will sinter togetherreadily before the metal core is melted and which has a melting pointhigher than the melting point of the core.

To provide an electrode having a coating which will be self-sustainingand project beyond the end of the rod during the welding operationthereby tending to increase the penetration of the arc and also causequiet operation.

The coating should be as flexible as possible to prevent chipping orflaking when bent or abused by striking.

The coating should be waterproof.

The coated rod should operate successfully with either a short are or along arc.

Other objects will be disclosed as my description proceeds.

The preferred embodiment of my invention comprises a copper rod providedwith a coating. The coating on rods in many instances comprisesprincipally a deoxidizer or reducing material 0 mixed with a binder suchas silicate of soda or a binder of varnish. The silicate of soda forms avery good binder so far as the material itself is concerned as it has afavorable influence upon the metal and are but it does not adhere wellto the rod and does not permit bending or abuse of the rod withoutchipping and also it is not waterproof. The coating formed with avarnish produces a varnish film about each particle of the materialforming the coating and is detrimentalto the benefits to be derived fromthe coating material and while the coating as such may be more or lessflexible and waterproof the varnish does not adhere well to a metalsurface.

I have found that if the ingredients of the coating are mixed withcasein glue in water, such a binder is far superior to the silicate ofsoda as it has a strong adhering property with respect to the metal rodand is not detrimental to the action of the coating ingredients properand isv more waterproof than silicate of soda.

I prefer to produce two coatings and the first coating or that lyingnext to the rod is preferably as follows by weight:-

, 7 Percent Calcium silicide (35% calcium or greater)- 450 Air floatedgraphite 25.0 Calcium carbonate (calcine)' 30.0

The above materials are preferably reduced to a very finely powderedstate as by means of a ball mill to pass a 200 mesh screen and with agiven weight of the dry mixture is compounded about an 80% weight of a13% solution of casein glue in water.

The copper rods are thoroughly cleaned as by sandblasting or pickling orboth and are then dipped into this material and allowed to dry.

The dry coating on a rod of about 5/32" diameter should increase thediameter of the rod by .015 to .018.

Material for a second coating is then prepared consisting of and in theproportion of 100 grams air floated graphite and 50 grams levigatedalumina (A1203) and one gallon of a rubber cement and if it is foundthat this mixture is too heavy then it may be thinned to a dippingconsistency by the addition of a rubber solvent, such as naphtha,gasoline, turpentine, dichlorethylene, etc. This coating is then appliedto the outside of the first coating by dipping and should increase thediameter of the rod by about .002. The graphite and alumina both assistin forming the projecting shell or coating and also tend to keep therubber coating from flowing when applied to the rod and before it sets.

The thickness of the two coatings for other diameters of rods would, ofcourse, vary to meet the requirements but such thickness can bedetermined by a few simple trials.

It will be found that a rod prepared as above described will form acrater around the fusing end of the rod, that is, the coating willproject beyond the end of the rod during welding for a short distanceand with a coating described as above the end of the projecting coatingwill be automatically consumed as the metal of the rod is deposited thuskeeping the projected length of the coating quite uniform.

The rubber binder may be of the rubber cement type, preferably what isknown as thermoplastic and thermoprene. The rubber binder, especiallythe thermoplastic type, has exceedingly strong adhesive properties andadheres tenaciously to the inner or first coating on the rod and atthesame time remains flexible after drying and for that reason binds theinner coating more securely in position and permits the rod to be bentor abused with less danger of the loss of the inner coating.

The thermoplastic material is also termed a heat-plastic rubber isomerand is a tough, tacky and non-friable rubber and may be purchased in theopen market in several forms and consistencies and under various tradenames. This material maybe prepared by masticating undissolved rubberwith a reagent adapted to convert it into an isomer having less chemicalunsaturation than rubber, then applying heat and causing an exothermalreaction between the two and then masticating the product. This may thenbe dissolved in ordinary rubber solvents such as gasoline or benzol.

This thermoplastic material has little or no detrimental effect upon thewelding characteristics and can be used in sufliciently large quantitiesto give-a satisfactory binding effect. The isomers are free fromvulcanizing materials and are preferred to rubber cements and solutionscontaining such vulcanizers as, for instance, sulphur, as the sulphurattacks the surface of the metal, especially copper, and forms asulphide of the metal which reduces the adhesion between the metal andits adjacent coating and affects the deposited metal.

Many coatings are very liable to chip or flake during the weldingoperation due to the intensive heat and lack of binding quality but Ifind that the outer coating above described prevents this detrimentalaction. I

The calcium in the inner coating has a decided quieting action upon thearc and tends to steady the same and prevent spitting and sputtering andit is found that the excessive cracking sound which usually takes placewhen the arc is interrupted, as by dropping molten metal, is avoided.

The silicon is a strong deoxidizer and such deoxidizer is foundnecessary when welding copper which is subject to very strong oxidationunder the heat of the electric arc.

The graphite, alumina and calcium carbonate may be said to form theprojecting coating or crater and maintain such projection beyond the endof the rod while under welding operation. The graphite is practicallyinfusible and hence tends to support the projecting coating, that is, it

may be said to act as the frame.

When I speak of a binder of animal origin or of animal glues I mean toinclude casein, bone glue, gelatin, alumina or blood glue, etc. whichmay be secured on the market and are practically waterproof when dry.

The coatings herein described may also be used on a rod of copper basealloy, that is, a rod outer coating either free of any ingredients orcontaining only one.

I claim:

1. A coated welding electrode comprising a fusible copper rod having aninner coating consisting of calcium silicide 45%, calcium carbonate 30%,raphite (preferably air-floated) 25%, all by weight, together with abinder of liquid casein glue and an outer coating superimposed on theinner coating consisting of 100 grams graphite,

50 grams alumina and 1 gallon of a rubber cement thinned with a solventif necessary, the consist-.- ency of the. solutions to be such as togive a deposit of the required amount of said coating material.

2. A coating for a welding electrode'comprising an air drying liquidcomposition consisting of calcium silicide, calcium carbonate, alumina(A1203) and graphite (preferably air-floated), all in a powdered stateand mixed with an aqueous solution of casein glue, the calcium silicidebeing of sufficient amount to quiet the arc and avoid oxidization of themolten metal and the other ingredients in sufficient quantities to forma projecting coating on the rod when welding.

'3. A coated welding rod comprising a nonferrous rod having a copperbase and two coatings, one superimposed upon the other, the innercoating comprising by weight and finely ground Per cent Calcium silicide44.0 Graphite 25.5 Calcium carbonate; 29.0 Alumina (A1203) 1.5

paste in which the rods are dipped and allowed to drain and dry and anouter coating of elastic rubber.

5. A coated welding rod comprising a metallic rod having a coatingcomprising calcium silicide between 40% and 50%, graphite between 20%and 30% and the balance calcium carbonate and alumina (Al2O3) all byweight and a sufiicient quantity of liquid casein glue to form a creamysolution in which to dip the rod. v

6. A coated welding rod comprising a metallic rod having a coatingcomprising calcium silicide between 40% and 50%, graphite between 20%and 30% and the balance calcium carbonate and alumina (A1202) all byweight and a suificient quantity of liquid casein glue to form a creamysolution in which to dip the rod and, an elastic outer coating ofrubber.

'7. A coating for a welding electrode comprising an air drying liquidcomposition consisting of calcium silicide, calcium carbonate, alumina(A1203) and graphite, all in a powdered state and mixed with a binder ofanimal glue, the calcium silicide being in sufi'icient quantity to quietthe arc and avoid oxidization. of the molten metal and theotheringredients in sufiicient quantities to form a projecting coatingfrom the end of the rod when welding.

'8. A coated welding rod comprising a nonferrous rod having a copperbase and two coatings, one coating superimposed upon the other, theinner coating comprising finely ground calcium silicide, graphite andcalcium carbonate mixed with an animal glue binder, the outer coatingcomprising alumina oxide (A1201) mixed with a binder of heat plasticrubber isomer, the calcium silicate being in sufiicient quantity toquiet the arc and prevent oxidization of the molten metal and the otheringredients insufiicient quantities to form a projecting sleeve from theend of the rod while welding.

' LOUIS A. MEISSE.

